Ummed Singh

Genetics- and genomics-based interventions for nutritional enhancement of grain legume crops: status and outlook

Meeting the food demands and ensuring nutritional security of the ever increasing global population in the face of degrading natural resource base and impending climate change is the biggest challenge of the twenty first century. The consequences of mineral/micronutrient deficiencies or the hidden hunger in the developing world are indeed alarming and need urgent attention. In addressing the problems associated with mineral/micronutrient deficiency, grain legumes as an integral component of the farming systems in the developing world have to play a crucial role. For resource-poor populations, a strategy based on selecting and/or developing grain legume cultivars with grains denser in micronutrients, by biofortification, seems the most appropriate and attractive approach to address the problem. This is evident from the on-going global research efforts on biofortification to provide nutrient-dense grains for use by the poorest of the poor in the developing countries. Towards this end, rapidly growing genomics technologies hold promise to hasten the progress of breeding nutritious legume crops. In conjunction with the myriad of expansions in genomics, advances in other ‘omics’ technologies particularly plant ionomics or ionome profiling open up novel opportunities to comprehensively examine the elemental composition and mineral networks of an organism in a rapid and cost-effective manner. These emerging technologies would effectively guide the scientific community to enrich the edible parts of grain legumes with bio-available minerals and enhancers/promoters. We believe that the application of these new-generation tools in turn would provide crop-based solutions to hidden hunger worldwide for achieving global nutritional security.

Soil Factors Associated with Micronutrient Acquisition in Crops- Biofortification Perspective

The introduction of high-yielding varieties, intensive cultivation systems, micronutrient-free fertiliser application, non-addition of organic manures and imbalanced plant nutrition has led to multi-micronutrient deficiencies in soils in many parts of the globe. Importance of micronutrients can be realised from their incredible functions in plants that result in quality produce, as each essential micronutrients play some specific functions in plants. Availability of micronutrients to plants is regulated by various soil factors such as texture, soil reaction, organic matter, clay content, soil moisture, nutrient interactions in soil, microbial activity, redox potential and aeration, etc. Research has, however, clearly indicated a sharp increase in micronutrient uptake and yield of crops by alleviating soil conditions through proper management practices, liming and applying micronutrients directly in soil or as foliar application. Moreover, exploitation of soil microbes such as micronutrient solubilisers and AM fungi has proven as boon in micronutrient uptake and improving soil quality. Maintenance of optimum soil organic matter status and balanced fertilisation or soil test-based fertiliser application also lead to biofortified farm produce, eliminate micronutrient deficiency and improve soil and plant health.

Biofortification of Food Crops

The chapters presented in this book Biofortification of Food Crops depict how agricultural technological interventions have true role in alleviating malnutrition. This book highlights the role of multidisciplinary approaches to cope up with the challenges of micronutrient malnutrition or hidden hunger which is an alarming public health issue in most parts of the world including India. In this endeavour, different biofortification approaches such as agronomic (or ferti-fortification), breeding, biotechnological, physiological, microbial etc. has fulfilled their different mandates of nutrient enrichment of food crops including cereals and pulses. The contents of the book proves that biofortified plants have adequate potential to nourish nutrient depleted soils, help increase crop productivity and provide nutritional benefits to plants, humans and livestock. The content and quality of information presented in this book will definitely provide multiple novel ideas of advance techniques and will stimulate innovative thoughts and directions amongst researchers and policy makers in the field of biofortification. In addition, the contributions presented in the book will be a good source of background knowledge and technical know-how to educate the readers about biofortification. The authors hope that the book entitled Biofortification of Food Crops would provide a suitable platform in our collective efforts for an appropriate dialogue among the scientists, researchers, entrepreneurs, policy makers and farmers in reducing the budding issues of malnutrition through novel approaches and means

Biofortification: Introduction, Approaches, Limitations, and Challenges

Micronutrient malnutrition is known to affect more than half of the world’s population and considered to be among the most serious global challenges to humankind. Modern plant breeding has been historically oriented toward achieving high agronomic yields rather than nutritional quality, and other efforts related to alleviating the problem have been primarily through industrial fortification or pharmaceutical supplementation. Micronutrient malnutrition or the hidden hunger is very common among women and preschool children caused mainly by low dietary intake of micronutrients, especially Zn and Fe. Biofortification, the process of increasing the bioavailable concentrations of essential elements in edible portions of crop plants through agronomic intervention or genetic selection, may be the solution to malnutrition or hidden hunger mitigation. The Consultative Group on International Agricultural Research has been investigating the genetic potential to increase bioavailable Fe and Zn in staple food crops such as rice, wheat, maize, common beans, and cassava.

Biofortification: Pathway Ahead and Future Challenges

A large share of global population is affected by mineral and vitamin deficiency, particularly in the developing countries. Recent estimates exposed the problem will be more disappointing in the near future. Biofortification is emerging as a potential crop-based approach to deal with the mineral malnutrition problem by enriching the density of bioavailable micronutrients and vitamins in food products. In recent years, significant advancement has been made in the fundamental understanding of micronutrient acquisition and translocation in soil-plant system. However, the current knowledge base in this area needs significant advancement to accelerate the pace of biofortification programme. Apart from the conventional breeding techniques, possible transgenic and agronomic approaches have also been identified for increasing the zinc, iron, selenium and iodine concentrations in the edible parts of food crops. Although these approaches are useful to address the mineral malnutrition problems worldwide, the effectiveness of the biofortification programme essentially relies on the farmers’ and consumers’ acceptance and future policy interventions. Therefore, strategic research and appropriate policy can lead to biofortification’s grand success in the near future. In this chapter, we discussed the current knowledge and future prospects of crop biofortification.

Mitigating pulse productivity constraints through phosphorus fertilization-a review

Pulses occupy an important position in food and nutritional security in India. Food security has been a major area of concern for agricultural scientists and planners in India since long. India produces over 200 million tonnes of foodgrains every year with an increase of four folds since independence. Increased efforts to produce more food have resulted in tremendous shift in cropping systems towards cereal-cereal based systems. But, still India is far behind in pulses production. In order to harness higher yields, phosphorus nutrition plays an important role besides other crop management factors. Hence, it is imperative to understand the constraints in pulse production to realize higher productivity and maintain soil health. P is important plant nutrient alongwith other major nutrients in pulses. This becomes more important when most of the Indian soils are P deficient and the farmers do not care for P nutrition in pulses resulting in lower pulse production, and making dependent on pulse imports for feeding the huge population causing sizable drain of foreign exchange.

Zinc Transporter: Mechanism for Improving Zn Availability

Zinc (Zn) is essentially required by plants for their growth and development. It plays very important role in various physiological procedures of plants such as photosynthesis, membrane integrity, protein synthesis, pollen formation, and immunity system. Although Zn is required by the plant in microconcentration, its bioavailable fraction in the soil is very low due to various soil factors. From soil solution it is absorbed by plants by root membrane transport mechanisms. After entering into plant system, it is neither oxidized nor reduced; but remains as divalent cation which has a great tendency to form tetrahedral complexes. From soil solution Zn reaches the plant root surface by three mechanisms, i.e., mass flow, diffusion, and root interception. Once it is absorbed, its transportation from roots to shoots occurs through the xylem and then easily retranslocated by phloem. This transport of ions and molecules from epidermal and cortical cell to xylem occurs through the symplastic or apoplastic route. The uptake of zinc into cells and its permeability into and out of intracellular organelles require some of the specific chemicals, generally known as transporter proteins. These proteins possess a quality to span the cell membranes which facilitate the movement of zinc. In recent years, a number of metal transporters have been identified in plants, including the P1B-ATPase family, zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP), natural resistance-associated macrophage protein (NRAMP) family, and cation diffusion facilitator (CDF) family. The bioavailable content of Zn in the soil can be increased using both chemical and biological approaches. Mineral fertilizers are considered a good source of Zn, but it gets fixed quickly on soil matrix, resulting in poor availability to plants. It is crucial to increase bioavailability of Zn to plants by solubilizing fixed Zn and/or by reducing fixation of the applied Zn fertilizers. This can be achieved either by using organic amendments or potential Zn solubilizing bioinoculants. Organic amendments improve bioavailability of Zn by increasing microbial biomass, which not only enhance the rate of decomposition of organic matter (source of Zn) but also enhance the bioavailability of indigenous Zn by lowering the soil pH and by releasing chelating agents. Similarly, exogenous application of some potential Zn solubilizing microflora has shown huge capability to improve bioavailable Zn content in the soil and its uptake by plant roots. This manuscript critically reviews about the Zn transporters and the role of rhizosphere microflora as a potential tool in enhancing its bioavailability to higher plants.

Effect of Sorghum Allelochemicals on the Mortality and Egg Hatching of Root-Knot Nematode, Meloidogyne javanica

Root exudates of sorghum plants collected via root exudates trapping system after proper fractionation, give rise a total of five allelofractions of different polarity range i.e. polar to non-polar. The fractions were found to enrich about one major compound in each which was extracted out in purity of 95% by repeatedly following the fractional crystallization and column chromatographic techniques. All these five compounds viz. C, B, A, E and D were converted to three Emulsifiable Concentrate (EC) and two Emulsive Water (EW) formulations. Laboratory bioassay experiments conducted during 2009 and 2010 at IIPR, Kanpur revealed that the Polarity of the compounds used in formulations play key role in imparting toxicity against second stage juveniles (J2) of Meloidogyne javanica. EC formulation of fractions C and B (non-polar) was found 100% toxic to the juveniles at 300 and 700 μg ml−1 concentrations, respectively at the 24 and 48 hours of incubation. EC and EW formulations of the fractions A and E (medium polarity) showed 100% toxicity at 1100 and 1500 μg ml−1 concentrations respectively, at an incubation period of 72 h, while EW formulation of fraction D (completely polar) found almost ineffective in all its test concentrations ranging from 1000–2000 μg ml−1. EC of C (highly non-polar) at 250 μg ml−1 also retarded in egg hatching of test nematode up to the extent of 98%. IR, 1HNMR, 13CNMR of C and B showed flavanol skeleton as a basic chemical moiety in their chemical structures, however, both differ structurally in respect of their functional substituents and the position of attachment at flavanol skeleton

Nitrogen and Legumes: A Meta-analysis

The current progress in agricultural production does not really cater to the demand of the burgeoning human population. Consequently, this puts global food and nutritional security at a great risk. This challenge calls for concerted efforts of all stakeholders to produce required quantity and quality of assured foods for ensuring food security. In the past, the principal driving force was to increase the yield potential of food crops and to maximize productivity. Today, the drive for productivity is increasingly combined with a desire for sustainability. For farming systems to remain productive and to be sustainable in the long term, it will be necessary to replenish the reserves of nutrients which are removed or lost from the soil. The nitrogen (N) inputs derived from atmospheric N via biological N fixation (BNF). Therefore, current farming systems need sustainable intensification through the inclusion of legume crops. This facilitates the precise use of nitrogen (N) by reducing their losses into the environment and ensures self-sufficiency in protein. The relevance of legumes in this context is enhanced as these crops offer numerous amenities that remain in line with prevalent sustainability principles. Legume crops provide protein-rich food, oil and fibre while supplying the 195 Tg N year−1 (also includes actinorhizal species) to the agroecosystem through the process of biological nitrogen fixation (BNF). Besides serving as the fundamental global source of good-quality food and feed, legume crops contribute to 15% of the N in an intercropped cereal and mitigate the emission of greenhouse gases (GHGs) by reducing the application demand of synthetic nitrogenous fertilizers. Legume cultivation releases up to seven times less GHGs per unit area than non-legume crops. Legumes allow the sequestration of carbon (1.42 Mg C ha−1 year−1) in soils and induce the conservation of fossil energy inputs in the system. The other benefits of legume crops include their significant positive impacts on biodiversity and soil health. Rotating legume crops with non-legume crops has the dual advantage of cultivating the legumes with slight or no extra N fertilizer. Care should be taken to ensure the availability of adequate N for the succeeding non-legume crops. The legume crops respond very well to conservation of agricultural practices. Overall, these characteristics are crucial to agriculture both in developing and developed countries apart from the conventional farming systems. Legumes in rotation promote exploration of nutrients by crops from different soil layers. They also help in reducing pressure on soil created by monocropping. Thus, crop rotation acts like a biological pump to recycle the nutrients. Hence, inclusion of legumes in the cropping system is inevitable to advance soil sustainability and food and nutritional security without compromising on the long-term soil fertility potential.

Grain Legumes for Resource Conservation and Agricultural Sustainability in South Asia

Degradation of natural resources is a major environmental concern that threatens the agroecosystem health and food security in South Asian countries. About 1.8 billion people (24% of world population) are living in this region in an area of 5.03 km2. The higher population pressure on agricultural land (7 person ha−1) has further threatened the existing resources to a great extent. Thus, conserving natural resource base is essential to feed the burgeoning population. Continuous practice of cereal-cereal rotation including rice-wheat in Indo-Gangetic plains have emerged several soil- and environmental-related issues. Diversification of cereal-cereal cropping systems is warranted to mitigate those issues and to adapt to the changing climatic condition and to enhance the resource-use efficiency on a sustainable basis. Grain legumes are the suitable candidate crop for diversification because of its inherent capacity to build up soil health and in conserving natural resources. There exists a large scope to introduce pulses as the second crop in 22.2 million hectare areas of rice fallows in India, Bangladesh, and Nepal. System intensification with inclusion of mungbean in summer fallows of rice-wheat cropping system could add an additional pulse crops area of 1.0 m ha in Indo-Gangetic plains. Several alternative grain legume inclusive crop rotations have been identified for the different agro-zones that certainly could play an important role in popularizing the conservation of agriculture in cereal-dominated production systems of South Asia. Endowed with an inherent potential biological N-fixation (30–150 kg N ha−1), of the deep root system, the root exudates mediated P-solubilization, and nutrient-rich residues of grain legumes improve the soil fertility and enhance the soil profile nutrient cycling. Crop diversification with grain legumes has additional benefits associated with improving water productivity, reducing input cost, and minimizing incidence of diseases and pests. Besides this, the low application rate of the N fertilizer to grain legumes has the advantage of reducing greenhouse gas emissions and groundwater pollution. Thus, grain legumes would play a crucial role in resource conservation, ecosystem balance, and in the sustainability of agricultural systems of South Asia.